Q. The radius of gyration of a disc of mass $50\ g$ and radius $2.5\ cm$, about an axis passing through its centre of gravity and perpendicular to the plane, is
A) $0.52\ cm$
B) $1.76\ cm$
C) $3.54\ cm$
D) $6.54\ cm$
Explanation
(b) $\frac{1}{2}MR^{2} = MK^{2} \Rightarrow K = \frac{R}{\sqrt{2}} = \frac{2.5}{\sqrt{2}} = 1.76cm$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.